1. Field of the Invention
The present invention relates to a clock signal generating circuit and a digital circuit system incorporating the same, and particularly relates to a clock signal generating circuit utilizing a multi-phase clock signal to generate clock signals having specific time delay and a digital circuit system incorporating the same.
2. Description of the Prior Art
In the field of digital logic operation, a register device such as a flip-flop is utilized for registering the temporary operation value or operation result of a digital logic operation circuit, and a pipeline structure is formed thereby. For such digital logic operation circuits, a whole operation can be regarded as separated by a plurality of registering devices to form a plurality of operation stages in the time domain. Each operation stage consists of a part of the logic operation circuit, which can perform a complete operation function. The above-mentioned registering devices can be triggered by clock signals to register the operation value of each operation state, and the frequency of clock signals determine the operation frequency of the digital logic operation circuit.
In practice, since the logic operation circuit including logic components must wait for a specific time to perform a desired operation due to the circuit delay thereof, a certain time delay exists between a registering device for triggering a previous operation stage and a registering device for triggering a next operation stage. In this situation, although the circuit design is correct, incorrect registered data may still be produced due to the wrong sampling time generated by the triggering registering devices. A delay circuit for generating the above-mentioned specific time delay usually consists of passive electronic devices such as resistors and capacitors. Therefore, the delay time is fixed. In this situation, the application of such a system is limited; that is, the digital logic circuit in whole may obtain grossly incorrect operation results if the frequency of the clock signal changes. Also, in CAD (Computer-Aided Design) applications, for example, the burden upon the processor will raise. In addition, such circuits will be largely influenced by PVT (Process, Voltage, and Temperature), and the synchronization of the signal will happen.